insidious

adjective

Definition of insidiousnext
as in treacherous
formal causing harm in a way that is gradual or not easily noticed Most people with this insidious disease have no idea that they are infected. an insidious enemy

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Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Recent Examples of insidious However, there is another, slower and more insidious evacuation taking place, and that is the steady migration from rural areas all around the world to burgeoning cities, which now host more than half the world’s population. — John Vaillant, Time, 8 Aug. 2026 This insidious method is a form of bullying, causing significant psychological harm and higher dissatisfaction than overt harassment. — Jason Walker Psyd, Forbes.com, 6 Aug. 2026 But there’s a market for a darker and more insidious explanation as to how the world works. — James Kirchick, The Atlantic, 29 July 2026 Meanwhile, an insidious supervillain (Kenneth Branagh) lurks, threatening to take Crown down. — Mya Copeland, Variety, 29 July 2026 See All Example Sentences for insidious
Recent Examples of Synonyms for insidious
  1. treacherous
  2. subtle
  3. perfidious
  4. deceptive
  5. false
  6. misleading
  7. deceitful
  8. incorrect
Adjective
  • Joshua has a treacherous district slate ahead but keep an eye out for the squad to keep building momentum in its final non-district bout against Eagle Mountain.
    — Charles Baggarly, Fort Worth Star-Telegram, 5 Sep. 2026
  • Rescuers are bracing for more treacherous weather amid search for those missing.
    — ABC News, ABC News, 31 Aug. 2026
Definition of treacherous
Adjective
  • Here, she’s matured as a well-rounded comedienne who can pull the stops for subtle approaches to laughs, and though the mugging is still evident, it’s only used for propitious moments.
    — Hank Grant, HollywoodReporter, 11 Sep. 2026
  • Comey’s nods to Drexler are mostly subtle, drawing from the artist’s color palette of vibrant hues from bright green and orange to cobalt blue and lilac, with an eye toward their high-contrast juxtapositions, a hallmark of Drexler’s paintings.
    — Maximilíano Durón, ARTnews.com, 11 Sep. 2026
Definition of subtle
Adjective
  • Logan Marshall-Green as Melanthius Melanthius is a perfidious goatherd who sides with Antinous.
    — Hannah Abraham, Forbes.com, 18 July 2026
  • This is perhaps the most perfidious practice of this sort of politics.
    — David M. Drucker, Twin Cities, 3 June 2026
Definition of perfidious
Adjective
  • López’s attorney sent Rivas and her group a cease-and-desist letter last month, citing trademark infringement and deceptive and unfair trade practices, the letter shows.
    — Sofia Saric, Miami Herald, 9 Sep. 2026
  • The technology was also tested against deceptive behaviour, an in a different scenario, fishing boats appeared to retreat while vessels from another direction accelerated toward the coastguard ship.
    — Bojan Stojkovski, Interesting Engineering, 30 Aug. 2026
Definition of deceptive
Adjective
  • However, data show that when AI is highly capable, doctors add more errors and false corrections than beneficial insights.
    — Abe Baker-Butler, STAT, 9 Sep. 2026
  • The company accused Fox News of airing false claims that voting machines were manipulated to help Joe Biden win the 2020 presidential election.
    — Los Angeles Times, Los Angeles Times, 9 Sep. 2026
Definition of false
Adjective
  • A matter of distance and brightness The stars that compose the Triangle — Vega, Altair, and Deneb — lie at very unequal distances from us, so their apparent brightness can give a misleading impression of their true luminosity.
    — Joe Rao, Space.com, 10 Sep. 2026
  • Publishers don’t want irrelevant or misleading ads to appear on their media sources.
    — Roman Vrublivskyi, Forbes.com, 10 Sep. 2026
Definition of misleading
Adjective
  • Bogus texts, mystery calls, deceitful emails all aimed at stealing your personal information and your money are relentless.
    — Donna Vickroy, Chicago Tribune, 13 Aug. 2026
  • The mutual trust and goodwill that xenia sought to cultivate has been eroded by this one deceitful act, creating a world that is defined by this moral violation.
    — Brianna Zigler, Entertainment Weekly, 19 July 2026
Definition of deceitful
Adjective
  • State officials stress that the incorrect information does not belong to another Michigan resident.
    — Terrance Friday, CBS News, 8 Sep. 2026
  • Manufacturers there can have the products reanalyzed, but dispensaries can’t sell those products until retesting shows the original analysis was incorrect.
    — Christopher Osher, ProPublica, 4 Sep. 2026
Definition of incorrect

Browse Nearby Words

inside tracks
insidious
insidiously
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Cite this Entry

“Insidious.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/insidious. Accessed 13 Sep. 2026.

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